Technical Field
[0001] The present invention relates to a novel process for producing egg yolk lecithin
having reduced phosphatidylethanolamine (herein abbreviated to PE) content and/or
containing substantially no impurities.
Background Art
[0002] Heretofore, a lipid fraction derived from egg yolk and containing phospholipids,
typically phosphatidylcholine (herein abbreviated to PC), namely, the so-called egg
yolk lecithin, is widely used in the field of cosmetics or pharmaceutical products
as an emulsifier or a liposome-forming agent as a carrier for drugs by virtue of the
surface activity, permeating effect and other properties of the phospholipids contained
therein.
[0003] It so happens that PC has the structure of cylindrical molecules comprising balanced
sizes of hydrophobic and hydrophilic groups, and when egg yolk lecithin with a high
PC content is used as a liposome-forming agent, it is therefore capable of forming
a liposome having a stable lipid bilayer. If egg yolk lecithin with a high PC content
and yet a low PE content is used in this case, it is possible to produce a liposome
having higher structural stability, i.e., a strong and pliant membrane. When used
as a starting material for cosmetics such egg yolk lecithin with a high PC content
and a low PE content is also capable of stabilizing various physical properties of
the end product.
[0004] In view of the above, if egg yolk lecithin with reduced PE content and relatively
increased PC content could be produced, such egg yolk lecithin would be highly beneficial
from a commercial point of view.
[0005] Egg yolk lecithin (lipid fraction) obtained by extraction from egg yolk by a conventional
method essentially comprises phospholipids, such as PC and PE, and neutral lipids,
such as triglyceride and cholesterol.
[0006] Various methods for fractionation of phospholipids from the egg yolk lecithin have
heretofore been known in the art. For example, Japanese Patent Laid-Open Pub. No.
152392/1984 discloses a method wherein a solution of a lipid fraction dissolved in
a non-polar or weakly polar solvent is brought into contact with a resin which adsorbs
phospholipids preferentially to cause the resin to adsorb the phospholipids, and thereafter
the phospholipids thus adsorbed are eluted with a polar solvent. In accordance with
this method, it is possible to obtain phospholipid fractions having different PE to
PC ratios by collecting the eluates according to fractions. However, a fraction having
a high PC content and a low PE content can be obtained only at an exceedingly low
proportional rate (about 10%) for the starting lipid fraction to be treated, and yet
copious quantities (about 200-fold (v/v) volume) of the resin is required for the
starting material. It is therefore difficult to fractionate by this method phospholipids
having a high PC content and a low PE content economically on a commercial scale.
[0007] Furthermore, various methods for increasing the PC component in egg yolk lecithin
have been attempted so far. For example, solvent fractionation which comprises adding
water to egg yolk lecithin dissolved in ethanol thereby to precipitate PE has been
known in the art. This method, however, is accompanied by a problem in that an increase
in PC content results in a notably low yield of the end product. As another example,
a method using an adsorbent such as silica gel or alumina has been known in the art.
This method, however, entails some difficulties when it is practiced on a commercial
scale such as that the yield of the end product is low although PC and PE can be fractionated
from each other effectively and that the adsorbent is required in great quantities.
Still another example of such known methods comprises forming a metal salt complex
with Cd, Ca, Mg, Zn or the like and utilizing the solubility thereof. However, this
method is again accompanied by the problem of the metal remaining inevitably in the
end product obtained.
[0008] Under such circumstances, a primary object of the present invention is to provide
a process whereby egg yolk lecithin with reduced PE content and relatively increased
PC content can be produced in a high yield on a commercial scale.
Disclosure of the Invention
[0009] As a result of extensive research effort expended toward attaining the above object,
we have found that, if egg yolk lecithin is dissolved in a polar solvent or a mixture
of a polar solvent and a non-polar solvent and thereafter brought into contact with
an ion exchange resin, the ion exchange resin will adsorb and remove substantially
only PE in the lipid components selectively and efficiently, and thus we have arrived
at the present invention on the basis of this finding.
[0010] More specifically, the present invention, in one aspect thereof, provides a process
for producing egg yolk lecithin with reduced PE content which comprises dissolving
egg yolk lecithin in a polar solvent or a mixture of a polar solvent and a non-polar
solvent, contacting the solution obtained with an ion exchanger, and then distilling
off the solvent from the solution.
[0011] We have examined the egg yolk lecithin thus obtained from the point of view of the
content of the residual impurities predominantly comprising inorganic salts and free
amino acids derived from the starting material and have unexpectedly found that substantially
no such impurities are detectable.
[0012] Thus, the present invention, in another aspect thereof, provides a process for producing
as the end product egg yolk lecithin having reduced PE content and containing substantially
no impurities by carrying out the above described process of the present invention
with the use of crude egg yolk lecithin containing inorganic salts and free amino
acids as major impurities or semipurified egg yolk lecithin as a starting material.
[0013] As a result of extended research, we have further found that the effect of removing
PE as well as impurities is proportionate mainly to the quantity of the ion exchange
resin used and that PE is removed after the impurities have been removed substantially
completely.
[0014] The present invention, in still another aspect thereof, can thus be said to provide
a process for producing as the end product egg yolk lecithin containing substantially
no impurities by the above described process of the present invention with the use
of crude egg yolk lecithin or semipurified egg yolk lecithin as a starting material.
Brief Description of the Drawings
[0016] FIGS. 1, 2 and 3 are graphs respectively showing the results of the tests conducted
in Examples 6, 7 and 8.
The Best Mode for Carrying Out the Invention
[0017] The present invention will now be described in detail.
[0018] The starting-material egg yolk lecithin to which the process of the present invention
is applicable is a lipid fraction containing phospholipids predominantly comprising
PC and obtained from egg yolk by a conventional method, for example, by solvent extraction
with ethanol, dichloromethane, hexane or ether. This lipid fraction is intended to
include a fraction containing inorganic salts (e.g., salts of sodium, potassium, calcium,
magnesium and iron) and free amino acids as primary impurities (crude egg yolk lecithin),
a fraction with reduced content of impurities obtained by subjecting crude egg yolk
lecithin to filtration through diatomaceous earth or a membrane filter (semipurified
egg, yolk lecithin), and a fraction with increased phospholipids content obtained
by treating crude egg yolk lecithin or semipurified egg yolk lecithin with acetone
and the like in accordance with a conventional method (egg yolk lecithin with increased
phospholipids content).
[0019] In other embodiments of the present invention, the starting material egg yolk lecithin
may comprise phospholipids and neutral lipids as primary constituents and/or may have
a high phospholipids content.
[0020] The solvent for egg yolk lecithin used in the process of the present invention is
a polar solvent, such as methanol, ethanol, acetone, dichloromethane or water, or
a mixture thereof with a non-polar solvent, such as n-peptane, n-hexane, n-heptane,
chloroform, ethyl acetate, ether or benzene. As will be apparent from the results
of the test examples which will be described later, a non-polar solvent alone cannot
effectively remove PE and impurities. While the mixing ratio between the polar solvent
and the non-polar solvent in the solvent mixture is not particularly limited, it is
generally preferable that the proportion of the polar solvent be higher.
[0021] The concentration of the egg yolk lecithin in the solvent, i.e., the concentration
of the egg yolk lecithin in the solution obtained, is preferably about 0.5 to 20%
(v/v). A concentration below 0.5% is not economical because an excessively great quantity
of solvent is required. If the concentration exceeds 20%, the solution will become
more viscous and therefore cannot be readily brought into contact with the ion exchange
resin in the subsequent step.
[0022] The ion exchange resin used herein is not particularly limited, and commercially
available strongly or weakly acidic cationic exchange resins or strongly or weakly
basic anionic exchange resins are suitable.
[0023] Specific examples of strongly acidic resins are Amberlite® IR 120B and 200C (supplied
by Rohm & Haas Co.); Dowex® 50W and MSC-1 (supplied by Dow Chemical Co.); DuoLite®
C-20 and C-25D (supplied by Diamond Shamrock Corp.); and Lewatit® S-100 and SP-120
(supplied by Farbenfabriken Bayer AG), while specific examples of weakly acidic resins
are Amberlite® IRC 50 and IRC 84; Dowex® CCR-2; DuoLite® CC-4; and Lewatit® CNP-80.
Strongly basic resins, on the other hand, include Amberlite® IRA 400 and IRA 900;
Dowex® 1 and MSA-1; DuoLite® A-101D; and Lewatit® M-500 and MP-500, while weakly basic
resins include Amberlite® IRA 68 and IRA 45; and Lewatit® MP-62. These resins may
be used singly or may also be used either in the form of a mixture of two or more
members irrespective of the species in any ratio or sequentially. For example, a mixture
of one acidic resin and one basic resin in a ratio of 1: 3 to 2: 1 is used. Advantageously,
the acidic resin is prepared in H form while the basic resin is prepared in OH form
in practice in order to improve adsorption efficiency.
[0024] The quantity of the ion exchange resin used can vary depending upon the quantity
of the PE and impurities contained in the starting-material egg yolk lecithin or the
particular type of the resin selected. In general, however, the ion exchange resin
may advantageously be used ordinarily in a volumetric quantity at least threefold
the volume of the PE contained in the starting-material egg yolk lecithin since the
resin in less than threefold volumes is insufficient to afford the effect of removing
the PE and impurities. Preferably, the volumetric quantity of the ion exchange resin
is suitably selected in the range of from 4.0- to 40-fold the volumes of the PE and
impurities in the starting material. Within this range, it is possible to reduce the
PE content to 2% or less which is defined as the maximum commercially permissible
residual PE content to trace amounts and also to remove impurities substantially completely.
Thus, the use of the resin in excess is not economical.
[0025] Since the PE is removed after the impurities have been removed substantially completely,
it is possible to produce egg yolk lecithin containing substantially no impurities
while retaining the PE content substantially at the level of that of starting material
by controlling the quantity of the ion exchange resin to be used in the practice of
the process of the present invention with the use of crude or semipurified egg yolk
lecithin as a starting material. In this case, the ion exchange resin may be advantageously
used in a volumetric quantity ordinarily at least 0.2-fold the volume of the starting-material
crude or semipurified egg yolk lecithin since the resin in less than 0.2-fold volumes
is insufficient to afford the effect of removing the impurities. Preferably, the volumetric
quantity of the ion exchange resin is suitably selected in the range of from 0.3-
to 3.0-fold the volume of the starting material depending on the quantity of the impurities
contained therein. If the resin is used in excess, the PE will also be removed.
[0026] The egg yolk lecithin solution may be brought into contact with the ion exchange
resin by passing the solution through a column packed with a predetermined quantity
of the resin by a conventional method or by supending a predetermined quantity of
the resin in the solution with stirring. This contact is advantageously carried out
at a temperature lower than the boiling point of the solvent from the point of view
of the prevention of the evaporation of the solvent.
[0027] In accordance with the process of the present invention, after the PE and/or impurities
have been caused to be selectively adsorbed on the ion exchange resin by the above
described contact, the solvent used is distilled off, for example, under reduced pressure,
from the solution subsequently to the selective adsorption in the case where the solution
has been passed through the column, or after the resin has been removed, for example,
by filtration in the case where the solution has been contacted with the resin by
stirring.
[0028] According to the process of the present invention as has been described hereinabove,
the PE content in the starting-material egg yolk lecithin can be reduced very effectively
and hence egg yolk lecithin with relatively increased PC content and containing substantially
no impurities can be produced. In addition, as will be apparent from the results of
the experimental examples, which will be described later, the PE content in the starting-material
egg yolk lecithin can be reduced to almost one half with the use of the ion exchange
resin in a quantity about 3-fold (v/v) the initial PE content. That is, only an extremely
small quantity of resin is required and, because the resin selectively adsrobs and
removes impurities and substantially only PE in the lipid components, the end product
can be obtained in a good yield. Thus, egg yolk lecithin containing substantially
no impurities while having an increased PC content and containing less or substantially
no PE can be produced on a commercial scale. Needless to say, the process of the present
invention, if repeatedly practiced, can be carried out more suitably for the desired
purpose.
[0029] Further, according to the process of this invention, egg yolk lecithin containing
substantially no impurities while retaining the PE content substantially at the level
of that of the starting-material egg yolk lecithin used can be produced on a commercial
scale by a remarkably simple procedure by suitably controlling the quantity of the
ion exchange resin to be used.
[0030] The advantageous effects of the present invention will now be described in greater
detail with reference to the results of experimental examples, it being understood
that all percentages set forth herein are % by weight unless otherwise indicated and
that both the egg yolk lecithin and PE have a specific gravity of approximately 1.
Experimental Example 1
[0031] This Experimental Example shows how the effect of removing PE and impurities according
to the process of the present invention varies depending on the species of the solvent
used.
[0032] 20g each of previously prepared egg yolk lecithin (PC; 58.0%, PE; 10.0%) was dissolved
respectively in 200 ml of absolute ethanol, n-hexane, chloroform, ethyl acetate, 95%
ethanol, and a chloroform-methanol-water (10:10:1) solution mixture. Each of the solutions
obtained was passed through a column packed with a mixture of 10 ml each of Amberlite®
IR 120B (H type) and Amberlite® IRA 400 (OH type) by a conventional method. The solvent
used was then completely distilled off from each solution under reduced pressure to
obtain the endproduct egg yolk lecithin sample.
[0033] With respect to each sample thus obtained, the residual PE content was measured by
means of IATROSCAN® Model TH-10; the quantity of the impurities was determined by
atomic absorption analysis in terms of metal ions; and further the quantity of free
amino acids was determined by amino acid analysis. The results obtained are summarized
in TABLE 1 below.
[0034] As is apparent from the above data, the contents of PE and impurities in the starting-material
egg yolk lecithin can be reduced very effectively when a polar solvent or a mixture
of a polar solvent and a non-polar solvent is used while, on the other hand, neither
PE nor impurities can be removed effectively when a non-polar solvent alone is used.
Experimental Example 2
[0035] This Experimental Example demonstrates that, in accordance with the process of the
present invention, PE can be removed effectively with the use of an exceedingly small
quantity of ion exchange resin.
[0036] 20 g (PE content: 4.0 g) each of previously prepared egg yolk lecithin (PC: 78.2%,
PE: 20.0%) was dissolved in 180 ml of 95% ethanol. Each of the solutions obtained
was passed through a column packed respectively with 2 ml, 4 ml, 6 ml, 8 ml, 10 ml,
12 ml, 14 ml, 16 ml and 20 ml of a mixture of Dowex® 50W (H type) and Dowex® 1 (OH
type) in equal quantity by a conventional method. The solvent used was then completely
distilled off from each solution under reduced pressure to obtain the end-product
egg yolk lecithin sample.
[0037] Subsequently, the residual PE content in each sample thus obtained was measured by
means of IATROSCAN® Model TH-10. The results are listed in the following TABLE 2.
[0038] As is noted from the above data, the PE content in the starting-material egg yolk
lecithin can be reduced to almost one half with the use of the resin in a quantity
about 3-fold (v/v) the initial PE content, and thus only an extremely small quantity
of resin is required in the process of the present invention.
Experimental Example 3
[0039] This Experimental Example shows how the effect of removing impurities varies depending
on the species of the solvent used in the case where only the impurities are intended
to be removed by controlling the quantity of the ion exchange resin used in the process
of the present invention.
[0040] 20 g each of previously prepared egg yolk lecithin (PC; 79.2%, PE: 20.0%, metal ions:
1,100 mg%, free amino acids: 800 mg%) was dissolved respectively in 200 ml of ether,
n-hexane, 95% ethanol, a chloroform-methanol (2: 1) solution mixture, and an n-hexane-acetone
(2: 1) solution mixture. To each of the solutions obtained were added 2 ml of Amberlite®
IR 120B (H type) and 3 ml of Amberlite® IRA 400 (OH type). The resulting solution
was stirred for 30 minutes and then filtered to remove the ion exchange resins. The
solvent used was thereafter completely distilled off from each solution under reduced
pressure to obtain the end-product egg yolk lecithin sample.
[0041] Subsequently, 5 w/v% emultion of each sample was prepared, and the electric conductivity
thereof was measured. The results obtained are set forth in TABLE 3 below.
[0042] Note: The electric conductivity of the starting-material egg yolk lecithin was 750
µS/cm.
[0043] It will be understood from the above data that the impurities in the starting material
can be removed very effectively when a polar solvent or a mixture of a polar solvent
and a non-polar solvent is used, whereas effective removal cannot be attained when
a non-polar solvent alone is used.
[0044] The present invention will now be described more fully in greater detail with reference
to specific examples of practice.
Example 1
[0045] 500 g of previously prepared egg yolk lecithin (PC: 56.9%. PE: 9.6%, cholesterol:
14.9%, triglyceride: 18.6%, metal ions: 960 mg%, free amino acids: 680 mg%, electric
conductivity: 690 µS/cm) was dissolved in 4.5 liters of 95% ethanol. The solution
obtained was passed through a column packed with a mixture of 500 ml of Amberlite®
IR 120B (H type) and 1,000 ml of Amberlite® IRA 400 (OH type) by a conventional method.
The solvent used was then completely distilled off from the solution under reduced
presure to obtain 450 g of egg yolk lecithin having a PE content reduced to 1.0%.
This product was found to comprise, in addition to PE, 62.0% of PC, 15.7% of cholesterol,
19.9% of triglyceride, 72 mg% of metal ions, and 59 mg% of free amino acid while having
an electric conductivity of 28 µS/cm.
Example 2
[0046] 200g of previously prepared egg yolk lecithin (PC: 79.6%, PE: 18.0%, cholesterol:
1.2%, metal ions: 1,100 mg%, free amino acids: 600 mg%, electric conductivity: 720
µS/cm) was dissolved in 2 liters of a chloroform-methanol-water (10: 10: 1) solution
mixture. The solution obtained was passed through a column packed with a mixture of
200 ml of Dowex® 50 W (H type) and 400 ml of Dowex® 1 (OH type) by a conventional
method. The solvent used was then completely distilled off from the solution under
reduced pressure to obtain 80 g of egg yolk lecithin having a PE content reduced to
1.0%. This product was found to comprise, in addition to PE, 96.1% of PC, 1.4% of
chlolesterol, 40 mg% of metal ions, and 20 mg% of free amino acid while having an
electric conductivity of 12 µS/cm.
Example 3
[0047] 500 g (PE content: 16.5 g) of previously prepared egg yolk lecithin (PC: 29.6%, PE:
3.3%, cholesterol: 4.3%, triglyceride: 62.3%, metal ions: 520 mg%, free amino acids:
210 mg%, electric conductivity: 230 µS/cm) was dissolved in 4.5 liters of 99.5% ethanol.
The solution obtained was passed through a column packed with a mixture of 25 ml of
Lawatit® S-100 (H type) and 25 ml of Lawatit® M-500 (OH type) by a conventional method.
The solvent used was thereafter completely distilled off from the solution under reduced
pressure to obtain 490 g of egg yolk lecithin having a PE content reduced to 1.6%.
This product was found to comprise, in addition to PE, 30.2% of PC, 4.5% of cholesterol,
63.1% of triglyceride, 73 mg% of metal ions, and 26 mg% of free amino acids while
having an electric conductivity of 32 µS/cm.
[0048] In all of Examples 1, 2 and 3 described above, egg yolk lecithin products with the
contents of PE and impurities respectively reduced to substantially the same levels
could be obtained even in the case where the egg yolk lecithin solution was brought
into contact with the ion exchange resin without using a column but simply by stirring.
Example 4
[0049] 100 g of previously prepared eg yolk lecithin (PC: 78.0%, PE: 18.3%, cholesterol:
2.0%, triglyceride: 0%, metal ions: 1,000 mg%, free amino acids: 700 mg%, electric
conductivity: 730 µS/cm) was dissolved in a hexane-ethanol (80: 20) solution mixture.
To the solution obtained were added 60 ml of Amberlite® IR 120B (H type) and 120 ml
of Amberlite® IRA 400 (OH type), and the resulting solution was stirred for mixing
for 30 minutes. Subsequently, the ion exchange resins were removed from the solution
by filtration, and the solvent used was completely distilled off under reduced pressure.
The resultant solution was then subjected to treatment with acetone to obtain 76 g
of egg yolk lecithin having a PE content of 0%. This product was found to comprise,
exclusive of PE, 96.8% of PC, 1.5% of cholesterol, 50 mg% of metal ions, and 12 mg%
of free amino acids while having an electric conductivity of 5.3 µS/cm.
Example 5
[0050] 2 kg of egg yolk lecithin (PC: 80.5%, PE: 17.3%, cholesterol: 0.5%, triglyceride:
0.1%, metal ions: 430 mg%, free amino acids: 180 mg%, electric conductivity: 120 µS/cm)
obtained by contacting dry egg yolk with supercritical carbon dioxide to extract the
fat component and subjecting the thus extracted fat component to treatment with ethanol
was dissolved in a chloroform-methanol-water (10: 10: 1) solution mixture. To the
solution obtained were addeed 1,000 ml of DuoLite® C-20 (H type) and 2,000 ml of DuoLite®
A-101D (OH type), and the resulting solution was stirred for mixing for 30 minutes.
[0051] Thereafter, the ion exchange resins were removed from the solution by filtration,
and the solvent used was completely distilled off under reduced pressure. The resultant
solution was then subjected to treatment with acetone to obtain 1.4 kg of egg yolk
lecithin having a PE content reduced to 2%. This egg yolk lecithin was found to comprise,
in addition to PE, 94.2% of PC, 0.8% of cholesterol, 0.1% of triglyceride, 48 mg%
of metal ions, and 16 mg% of free amino acids while having an electric conductivity
of 7.3 µS/cm.
Examples 6, 7 and 8
[0052] In the respective Examples, the crude egg yolk lecithin materials shown in TABLE
4 were dissolved in the solvents shown in the same TABLE to prepare the necessary
number of solutions for each material. To the solutions thus prepared for each material
were added in varying quantities the ion exchange resin mixtures shown in the same
TABLE, and the resulting solutions were stirred for mixing for 30 minutes at normal
temperature (20°C). The resins used were removed bi filtration, and the solvent was
then completely distilled off from the respective solutions under reduced pressure
to obtain egg yolk lecithin samples corresponding to the quantities of the resins
used.
[0053] Subsequently, the contents of the residual PE and impurities in the samples obtained
in the respective Examples were measured by the method employed in Experimental Example
1. The results obtained are shown by graphs for the respective Examples (FIGS. 1,
2 and 3).
[0054] Examples 9, 10, and 11 set forth hereinbelow are examples wherein only the impurities
in the starting-material egg yolk lecithin are removed by controlling the quantity
of the ion exchange resin used in the process of the present invention within a predetermined
range.
Example 9
[0055] 1,200 g of previously prepared egg yolk lecithin (PC: 51.7%, PE: 10.2%, neutral lipids:
37.2%, free amino acids: 660 mg%, metal ions: 1,090 mg%, electric conductivity: 566
µS/cm) was dissolved in 12 liters of water-saturated dichloromethane. To the solution
obtained were added 200 ml of Amberlite® IR 120B (H type) and 400 ml of Amberlite®
IRA 400 (OH type), and the resulting solution was stirred for mixing for 30 minutes.
Thereafter, the ion exchange resin used were removed by filtration, and the solvent
was then completely distilled off under reduced pressure to obtain 1,170 g of purified
egg yolk lecithin. This purified egg yolk lecithin was found to comprise 52.0% of
PC, 10.0% of PE, 37.3% of neutral lipids, 37 mg% of free amino acids, and 180 mg%
of metal ions while having an electric conductivity of 6.4 µS/cm.
[0056] Subsequently, the solubility of the thus obtained purified egg yolk lecithin in an
organic solvent was tested in comparison with that of the starting material. The results
are presented in TABLE 5. In order to test the solubility, 10 w/v% solutions of the
starting and purified egg yolk lecithin samples were prepared by using the respective
solvents.
Example 10
[0057] 500 g of previously prepared egg yolk lecithin (PC: 79.9%, PE: 16.6%, neutral lipids:
1,7%, free amino acids: 570 mg%, and metal ions: 1,100 mg% while having an electric
conductivity of 750 µS/cm) was dissolved in 3 liters of an n-hexane-acetone (2: 1)
solution mixture. To the solution obtained were added 250 ml of Dowex® 50 W (H type)
and 250 ml of Dowex® 1 (OH type), and the resulting solution was stirred for mixing
for 15 minutes. The ion exchange resins used were then removed by filtration, and
thereafter the solvent was completely distilled off under reduced pressure to obtain
490 g of purified egg yolk lecithin. This purified egg yolk lecithin was found to
comprise 79.8% of PC, 16.4% of PE, 1.8% of neutral lipids, 10 mg% of free amino acids,
and 127 mg% of metals while having an electric conductivity of 29 µS/cm.
[0058] Subsequently, the solubility of the thus obtained purified lecithin in an organic
solvent was tested in accordance with the procedure of the preceding Example 9 in
comparison with that of the starting material. The results are set forth in TABLE
6.
Example 11
[0059] 1,000 g of previously prepared egg yolk lecithin (PC: 77.0%, PE: 17.5%, neutral lipids:
4.6%, free amino acids: 274 mg%, metal ions: 346 mg%, electric conductivity: 250 µS/cm)
wad dissolved in 5 liters of a chloroform-methanol-water (10: 5: 1) solution mixture.
To the solution obtained were added 50 ml of DuoLite® C-20 (H type) and 150 ml of
DuoLite® A-101D (OH type), and the resulting solution was stirred for mixing for 30
minutes. Thereafter, the ion exchange resins used were removed by filtration, and
the solvent was then completely distilled off under reduced pressure to obtain 980
g of purified egg yolk lecithin. This purified egg yolk lecithin was found to comprise
77.6% of PC, 16.5% of PE, 4.8% of neutral lipids, 45 mg% of free amino acids, and
190 mg% of metal ions while having an electric conductivity of 28 µS/cm.
[0060] Subsequently, the solubility of the thus obtained purified lecithin in an organic
solvent was tested in accordance with the procedure of Example 9 described above in
comparison with that of the starting material. The results are shown in TABLE 7 below.
Industrial Applicability
[0061] The egg yolk lecithin obtained by the process of the present invention, in one embodiment
thereof, is egg yolk lecithin having a PE content reduced to an extent wherein it
has been very effectively lowered or wherein the lecithin is substantially free of
PE while having a relatively increased PC content yet containing substantially no
impurities, and is therefore expected to have wider application in various fields,
especially in the fields of pharmaceutical products and cosmetics.
[0062] The egg yolk lecithin obtained by the process of the present invention, in another
embodiment thereof, is egg yolk lecithin retaining the PE content substantially at
the level of that of the starting-material egg yolk lecithin used, i.e., retaining
the phospholipid composition of the starting material, while excluding substantially
only impurities, and is therefore expected to have wider application in various fields
as one purified phospholipid material, for example, as an emulsifier. Especially,
it has hitherto been difficult to substantially completely remove from crude egg yolk
lecithin impurities such as inorganic salts, free amino acids and polypeptides, so
that egg yolk lecithin does not readily dissolve in ordinary organic solvents, and
thus the applicability thereof has been limited. In accordance with the process of
the present invention, egg yolk lecithin containing substantially no such impurities
and having remarkably improved solubility can be obtained whereby wider application
of the egg yolk lecithin can be expected.
1. process for producing egg yolk lecithin having reduced PE (phosphatidylethanolamine)
content which comprises dissolving egg yolk lecithin in a polar solvent or a mixture
of a polar solvent and a non-polar solvent, contacting the solution obtained with
an ion exchange resin, and then distilling off the solvent from the solution.
2. A process as claimed in claim 1, wherein the starting-material egg yolk lecithin
is crude egg yolk lecithin containing inorganic salts and free amino acids as major
impurities or semipurified egg yolk lecithin, and the product obtained after the distillation
of the solvent off is egg yolk lecithin having reduced PE content and containing substantially
no impurities.
3. A process as claimed in claim 1, wherein the starting-material egg yolk lecithin
comprises phospholipids and neutral lipids as primary constituents.
4. A process as claimed in claim 1, wherein the starting-material egg yolk lecithin
has a high phospholipids content.
5. A process as claimed in any of claims 2, 3 and 4, wherein the ion exchange resin
is used in a volumetric quantity at least 3-fold the volume of the PE in the starting-material
egg yolk lecithin.
6. A process as claimed in claim 5, wherein the ion exchange resin is used in a volumetric
quantity in the range of from 4.0- to 40-fold the volume of said PE.
7. A process as claimed in any of claims 1 through 6, wherein the polar solvent is
selected from methanol, ethanol, acetone, dichloromethane and water.
8. A process as claimed in any of claims 1 through 7, wherein the concentration of
the egg yolk lecithin in the solvent is 0.5 to 20% (v/v).
9. A process for producing egg yolk lecithin containing substantially no impurities
which comprises dissolving crude egg yolk lecithin containing inorganic salts and
free amino acids as major impurities or semipurified egg yolk lecithin in a polar
solvent or a mixture of a polar solvent and a non-polar solvent, contacting the solution
obtained with an ion exchange resin, and then distilling off the solvent from the
solution.
10. A process as claimed in claim 9, wherein the ion exchange resin is used in a volumetric
quantity at least 0.2-fold the volume of the starting-material crude egg yolk lecithin
or semipurified egg yolk lecithin.
11. A process as claimed in claim 10, wherein the ion exchange resin is used in a
volumetric quantity in the range of from 0.3- to 3.0-fold the volume of the starting-material
crude egg yolk lecithin or semipurified egg yolk lecithin.
1. Procédé de fabrication de lécithine de jaune d'oeuf ayant une teneur réduite en
PE (phosphatidyléthanolamine), qui comprend:
- la dissolution de lécithine de jaune d'oeuf dans un solvant polaire ou un mélange
d'un solvant polaire et d'un solvant non-polaire;
- la mise en contact de la solution obtenue avec une résine échangeuse d'ions; puis
- l'élimination par distillation du solvant à partir de la solution.
2. Procédé selon la revendication 1, dans lequel la lécithine de jaune d'oeuf en tant
que matière de départ est la lécithine de jaune d'oeuf brute contenant des sels minéraux
et des acides aminés libres en tant qu'impuretés majeures, ou la lécithine de jaune
d'oeuf semi-purifiée, et le produit obtenu après l'élimination par distillation du
solvant est une lécithine de jaune d'oeuf ayant une teneur en PE réduite et ne contenant
pratiquement pas d'impuretés.
3. Procédé selon la revendication 1, dans lequel la lécithine de jaune d'oeuf en tant
que matière de départ comprend des phospholipides et des lipides neutres en tant que
constituants primaires.
4. Procédé selon la revendication 1, dans lequel la lécithine de jaune d'oeuf en tant
que matière de départ présente une teneur élevée en phospholipides.
5. Procédé selon l'une des revendications 2, 3 et 4, dans lequel la résine échangeuse
d'ions est utilisée dans une quantité volumétrique d'au moins 3 fois le volume de
la PE dans la lécithine de jaune d'oeuf en tant que matière de départ.
6. Procédé selon la revendication 5, dans lequel la résine échangeuse d'ions est utilisée
dans une quantité volumétrique se situant dans la plage allant de 4,0 à 40 fois le
volume de ladite PE.
7. Procédé selon l'une des revendications 1 à 6, dans lequel le solvant polaire est
choisi parmi le méthanol, l'éthanol, l'acétone, le dichlorométhane et l'eau.
8. Procédé selon l'une des revendications 1 à 7, dans lequel la concentration de la
lécithine de jaune d'oeuf dans le solvant va de 0,5 à 20% (v/v).
9. Procédé de fabrication de lécithine de jaune d'oeuf ne contenant pratiquement pas
d'impuretés, qui comprend:
- la dissolution de lécithine de jaune d'oeuf brute contenant des sels minéraux et
des acides aminés libres en tant qu'impuretés majeures ou de la lécithine de jaune
d'oeuf semi-purifiée dans un solvant polaire ou un mélange d'un solvant polaire et
d'un solvant non-polaire;
- la mise en contact de la solution obtenue avec une résine échangeuse d'ions; puis
- l'élimination par distillation du solvant à partir de la solution.
10. Procédé selon la revendication 9, dans lequel la résine échangeuse d'ions est
utilisée dans une quantité volumétrique d'au moins 0,2 fois le volume de la lécithine
de jaune d'oeuf brute ou de la lécithine de jaune d'oeuf semi-purifiée en tant que
matière de départ.
11. Procédé selon la revendication 10, dans lequel la résine échangeuse d'ions est
utilisée dans une quantité volumétrique se situant dans la plage allant de 0,3 à 3,0
fois le volume de la lécithine de jaune d'oeuf brute ou de la lécithine de jaune d'oeuf
semi-purifiée en tant que matière de départ.
1. Verfahren zum Herstellen von Eigelb-Lezithin mit vermindertem PE (Phosphatidyläthanolamin)
Anteil, bei dem Eigelb-Lezithin in einem polaren Lösungsmittel oder einem Gemisch
aus einem polaren Lösungsmittel und einem nichtpolaren Lösungsmittel die erhaltene
Lösung mit einem Ionenaustauschharz in Berührung gebracht und dann das Lösungsmittel
aus der Lösung abdestilliert wird.
2. Verfahren nach Anspruch 1, bei dem das Eigelb-Lezithin-Ausgangsmaterial ein Roh-Eigelb-Lezithin,
das als Hauptverunreinigungen anorganische Salze und freie Aminosäuren enthält, oder
halbgereinigtes Eigelb-Lezithin ist, und bei dem das nach der Abdestillation des Lösungsmittels
enthaltene Produkt ein Eigelb-Lezithin ist, das einen verminderten PE Anteil aufweist
und im wesentlichen keine Verunreinigungen enthält.
3. Verfahren nach Anspruch 1, bei dem das Eigelb-Lezithin-Ausgangsmaterial als Hauptbestandteile
Phospholipoide und neutrale Lipoide enthält.
4. Verfahren nach Anspruch 1, bei dem das Eigelb-Lezithin-Ausgangsmaterial einen hohen
Anteil an Phospholipoiden aufweist.
5. Verfahren nach einem der Ansprüche 2, 3 oder 4, bei dem das Ionenaustauschharz
in einer volumetrischen Menge von zumindest dem dreifachen des Volumens des im Eigelb-Lezithin-Ausgangsmaterial
enthaltenen PE verwendet wird.
6. Verfahren nach Anspruch 5, bei dem das Ionenaustauschharz in einer volumetrischen
Menge im Bereich zwischen dem 4,0 und dem 40-fachen des Volumens des PE verwendet
wird.
7. Verfahren nach einem der Ansprüche 1-6, bei dem das polare Lösungsmittel Methanol,
Äthanol, Aceton, Dichlormethan oder Wasser ist.
8. Verfahren nach einem der Ansprüche 1-7, bei dem die Konzentration des Eigelb-Lezithins
im Lösungsmittel 0,5-20% (v/v) beträgt.
9. Verfahren zum Herstellen von Eigelb-Lezithin, das im wesentlichen keine Verunreinigungen
enthält, bei dem rohes Eigelb-Lezithin, das als Hauptverunreinigungen anorganische
Salze und freie Aminosäuren enthält, oder halbgereinigtes Eigelb-Lezithin in einem
polaren Lösungsmittel oder einem Gemisch aus einem polaren Lösungsmittel und einem
nicht-polaren Lösungsmittel gelöst, die erhaltene Lösung mit einem Ionenaustauschharz
in Berührung gebracht und dann das Lösungsmittel aus der Lösung abdestilliert wird.
10. Verfahren nach Anspruch 9, bei dem das Ionenaustauschharz in einer volumetrischen
Menge von zumindest dem 0,2-fachen des Volumens des als Ausgangsmaterial führenden
rohem Eigelb-Lezithins oder des halbgereinigten Eigelb-Lezithins verwendet wird.
11. Verfahren nach Anspruch 10, bei dem das Ionenaustauschharz in einer volumetrischen
Menge im Bereich vom 0,3-3,0-fachen des Volumens des als Ausgangsmaterial dienenden
Roh-Eigelb-Lezithins oder des halbgereinigten Eigelb-Lezithins verwendet wird.